Accuracy is critical to sport. In tennis, for example, the serve is practiced with repetitive drills intended to develop an accurate and powerful serve. There are several methods known in the art for developing accuracy skills that provide user feedback. One is for the coach to build a pyramid consisting of four tennis balls. The balls are placed in a desired practice location and the player is instructed to hit the pyramid. When the pyramid is hit, the balls are scattered, the coach or player is forced to retrieve them, taking valuable time from practice sessions. Often it takes longer for the coach to set up the target than for the player to disrupt it. Placing multiple targets simultaneously is often counter productive as scattered pyramids frequently topple other pyramids.
While a number of electronic targets have been proposed to provide a more repeatable and less time-consuming feedback means, none are used, due to one or more of the following reasons:
1) Cost--Some of the prior art targets incorporate highly expensive components. PA1 2) Poor simulation of normal playing conditions--While the player focuses primarily on accuracy, the coach analyses spin and power, as judged by the bounce after striking the target. An ideal tennis target will bounce the ball accurately after striking the target. Furthermore, an ideal target will have its topmost surface contiguous or nearly contiguous with the playing surface. PA1 3) A sense of fun and mental stimulation--It is well-known that practice must remain fun and interesting to maintain player motivation. There is a sense of satisfaction that comes from scattering the pyramid of balls that is not provided by the "beep" or flash of prior art targets. An ideal target could be readily modified to provide customized feedback for each student thereby providing a sense of fun and mental interest. PA1 4) Portability--Were targets useful and economically viable, they would be moved back and forth on a daily or even hourly basis, requiring them to be light and highly transportable in order to be practical. For example, at the beginning and end of each day, many targets (a dozen or so) would be moved simultaneously, necessitating lightness. PA1 5) Adaptability--Targets must be easily adaptable to the needs of each student. They must allow ready placement to any location.
Prior art targets include most pertinently: U.S. Pat. No. 3,874,664 to Faurot et al. which offers a rigid flat panel, however with several drawbacks. The rigid sandwich construction, required to create an inner chamber capable of transmitting a pressure wave, necessitates a device of substantial thickness, thereby poorly mimicking the true nature of the playing surface both in terms of its thickness and in the deflection associated with a large diaphragm. Furthermore, pressure sensors are relatively expensive. The high weight of the device also renders it impractical. U.S. Pat. No. 3,415,517 to Krist employs metal wires or strips built into the court, providing a highly expensive and completely non-adaptable system. Indeed, the system was designed as a judging function, for which it performs well, but cannot be adapted to suit the present need. Other wide area sensors include a compliant, force sensitive top surface that strongly affects the flight of the ball and are therefore undesirable. Force sensitive materials such as force sensitive resistiors, and piezo films are far too expensive.
Therefore, what is desirable is a sport target that provides feedback to both player and coach that does not contain inherently expensive components. It is further desirable to simulate normal playing conditions with respect to both bounce and spin, and without having significant thickness. It is further desirable for the target to be light and portable so that a dozen may be comfortably carried to and from a storage facility to the place of use. It is yet further desirable to have a flexible feedback system between coach and student that allows the training regimen to remain varied and fun, a system that stimulates the mind as well as the muscles by offering variation and novelty in the practice regimen.